AUSTIN (AP) – Gov. Rick Perry isn’t on the ballot, but a new member of the Bush dynasty is. Wendy Davis can clinch a feat no woman has achieved in Texas since Ann Richards. Heavyweight Republicans are trying to survive, and a new voter ID law gets a major test.

Throw in a March blast of winter weather delaying the opening of some polling sites, and Texas’ primary elections Tuesday figure to be anything but ordinary.

The results will begin the biggest reshuffling of state power in a decade. Although most of the competitive primary races are on the Republican side, Davis’ bid for governor headlines a roster of underdog Democrats girding instead for the Nov. 4.

That’s the only day that matters to Davis and Republican Attorney General Greg Abbott in the year’s marquee showdown. Neither has a competitive primary, leaving Davis poised to become the first female gubernatorial nominee in Texas since Richards in 1994, and Abbott the first new GOP nominee after 14 years of Perry.

But a frigid forecast could leave voters with a dangerous drive to the polls, or shutter some sites altogether. By late Monday, Travis County officials announced that polls around Austin would open on a four-hour delay.

Meteorologists say freezing rain overnight Tuesday could sock Central Texas, the Houston area should be wary of elevated roads and a biting cold will be felt most everywhere.

“It doesn’t take much when you’re not used to winter weather,” National Weather Service meteorologist Dennis Cavanaugh said.

Polling locations cannot be kept open past 7 p.m. without a court order. State elections officials late Monday urged counties in the path of the worst weather to begin preparing for the scenario.

“If you determine that it is unsafe, it is best to open the location late, move the location, or close the location,” read the advisory from the Texas secretary of state’s office.

Unlike Davis and Abbott, few other Texas candidates have the luxury of uneventful primaries.

State elections officials Monday instructed counties that if polls are open late because of bad weather, they must also stay open later.

The conservative star power of U.S. Sen. Ted Cruz has GOP candidates — from local races to statewide offices — jostling farther right and wooing voters with vows to emulate Cruz’s no-compromise style. Even U.S. Sen. John Cornyn and U.S. Rep. Pete Sessions, two of the state’s most powerful Republicans, have spent money campaigning against longshot challengers who say the incumbents have grown moderate in Washington.

But changes are far more likely in Austin. Republican Lt. Gov. David Dewhurst, who lost to Cruz for the Senate seat in 2012, appears headed for his first runoff in 11 years on the job.

Millions of dollars have been spent between Dewhurst and three prominent challengers: state Sen. Dan Patrick, Land Commissioner Jerry Patterson and Agriculture Commissioner Todd Staples. The race has been the nastiest and most competitive this primary season, with the four all taking aim at President Barack Obama in television ads when they’re not sniping at each other.

Primary runoffs are set for May 27. Settling GOP nominations for attorney general, comptroller and agriculture commissioner may also have to wait until then.

“When there’s a fair amount of negative out there it makes the electorate very unpredictable,” Patterson said Monday. “You couldn’t accurately poll it — or you could and that poll would be good for probably about four hours.”

Noticeably absent this primary season has been Perry, who announced last summer he wouldn’t seek re-election but continues mulling a 2016 run for president. The longest-serving governor in Texas history hasn’t endorsed in major races or even heard his name mentioned much in campaigns by his fellow Republicans.

They’ve instead talked about the future of the Texas GOP, which is expected to include George P. Bush in a prominent role. The 37-year-old nephew of former President George W. Bush, and son of former Florida Gov. Jeb Bush, is running for land commissioner.

“Help is on the way,” Bush told supporters in El Paso on Monday. “After this primary season, we will go out there and fight the good fight.”

For Democrats, who haven’t won a statewide election in 20 years, the primary serves little but an early test of voter strength. A team of Obama campaign veterans launched the group Battleground Texas last year to give Democrats a chance and will watch turnout Tuesday to gauge their efforts so far.

Another race being closely watched Tuesday night involves U.S. Rep. Ralph Hall, who at age 90 is the oldest member of Congress. Five GOP challengers are vying against him in an effort to deny him an 18th term.

Election administrators say the primary will be the first real test of the state’s new voter ID law, which the Republican-controlled Legislature passed in 2011 but wasn’t enacted until last summer amid legal challenges. No major problems or controversies flared when the law debuted in November during a low-turnout, off-year election.